Back to Ganoksin | FAQ | Contact

Polishing ametrine rough with a Dremel tool


#1

I recently purchased some lovely ametrine faceting rough (17-20 ct.
pieces). My intention is to use these pieces as they are, unfaceted;
however, I want to give them a high polish. Eventually I might be
interested in doing some serious faceting and polishing, but I’m not
there yet, so I do not have appropriate equipment or materials (and
for that matter, I don’t know jack about it). I’m also not interested
in tumbling these pieces; I want to preserve the angles and edges.
What I’d like to know is can I use a Dremel tool to do this, and what
bits and grits, etc. would I need, and how would I proceed? Can
anyone out there in Orchidland enlighten me? (We’re talkin’ resident
dummy here, so please talk down to me.)

Thanx, so much, for any help anyone can provide.

Tamara


#2

Hi Tamara,

I regret to start by telling you this probably isn’t what you want
to hear. I think you’re probably considering a great way to turn some
fine rough into scrap. If you really want to use a Dremel for this
purpose, at least practice on some cheap “throw away” rough.

If your Dremel is like mine, it has a motor in it and is running on
110v AC Power. Grinding stone, especially something as hard as
quartz, requires a constant flow of water. The two are not usually a
pleasant combination. A flexible shaft type arrangement would be
better. My recommendation would be to keep the material until you can
save up to buy the proper equipment.

That being said, it is theoretically possible to cut a flat
surface with a small round wheel, like that used on a Dremel or
Foredom. However, an experienced lapidary (gem cutter) would be quick
to tell you it is very difficult. Faceters use flat “laps”, thus the
term “lapping” for grinding a flat surface.

Assuming for the moment that you were to undertake such an endeavor,
you would want diamond (preferably), or silicon carbide tools for
your Dremel. Silicon carbide, being much the same hardness as quartz
(i.e., ametrine) would be a “hard row to hoe.” Understanding the
relative hardness of minerals is paramount in being able to cut
gemstones successfully.

You would also need a successively finer series of “grits” to finish
the stone. Rough grind with 100-200 grit (depending on the hardness
of the material), then finish sanding with 400-600, then 1200, and
maybe higher. Then polish with an appropriate compound. I still use
John Sinkankas as a reference.

I don’t mean to discourage you. Save up, and buy the right
equipment! Shop around and keep your eyes open! You’ll find what you
need if you put your “feelers” out! :slight_smile:

All the best.

Dave

Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com


#3

Tamara, I would not attempt to work any stone (especially a quartz
stone) until I had the knowledge of lapidary. You should go to a
local library and look up lapidary and learn a little about the
grinding of rocks before you grind on this crystal. Quartz can be
one nasty stone to grind with a motor tool. Even accomplished
lapidaries shun working on quartz carvings. Quartz is chippy, heat
sensitive, and easily stress to internal breakage. Get some
education before you attempt this endeavor.

Gerry Galarneau


#4

Tamara, Please don’t use your Dremel on good rough, it just doesn’t
afford adequate control to cut and polish a nice piece. (probably not
a flex-shaft either, although some experienced carvers do use them) I
think I know what you have in mind for them - a nice polished surface
maintaining the basic shape of the stone, but in sort of a freeform
semi-faceted shape that lends itself to cool design. (they called them
"cabocet" stones in the '50s - Cut on a standard cabachon machine)
They were the early forerunners of some of the great lapidary work
being done today. Almost works of art in themselves, but always
intended to be set in jewelry. Perhaps it is time for a revival of
this technique? If you contact me off list, I can send you some pics
when I get some more cut, they seem to be rather popular. (Out of
stock right now and alas, no pics from the last batch) You might want
to check e-Bay for stone cutting equipment. Sometimes they have some
very good deals. And, of course, get some books on lapidary arts as
stone cutting can sometimes get rather involved. (although quartz is
pretty easy)

Mark Thomas Ruby
SunSpirit Designs
Loveland, CO
970 669-7075


#5

Hi, Tamara- You may need some trial and error on this, but if I were
trying to polish a crystal with a dremel or other flexshaft without
changing the shape, I would use diamond paste on soft cotton buffs.
start with 600 grit diamond paste, follow with 1200, and then finish
with the 14,000 grit diamond polish. Use a separate buff for each
grit. The best diamond polish I have found is called "super polish"
and is available from a company called “Mountain Mist.”

http://www.mtmist.org/

The usual disclaimers follow, I am not affiliated with Mountain Mist
and do not profit in any way from this recommendation, I am just a
satisfied customer.

If you can’t get a polish using this procedure, you may need to
begin again starting with a 325 grit diamond paste, but you will want
to proceed with caution if you do, because 325 grit is coarse enough
to agressively carve into the crystal, and it sounds like you want to
preserve the original shape.

Lee Einer
http://members.cox.net/appealsman/


#6

Tamara - I suggest that you check out the nearest rock/gem club, and
recruit help from among the members. Using a hand piece to work
"hard" stone (all forms of quartz qualify as hard stone) is not for
the novice, especially if you want to obtain optimum results.

Jim Small
Small Wonders


#7

Hi Tamara You would do better to buy a few pieces of 18 or 16 ga.
copper sheet, make sure they are dead flat. Then score them with an
exacto knife and a ruler in a crisscross pattern. Then add a little
oil, vegetable oil or sewing machine oil, and add the appropriate
diamond grit. Dop your stone, that is using wax or krazy glue, attach
a stick (handle) to it, or use your fingers if stone is large enough.
For extra lubrication a few drops of liquid soap in a cup of water in
a pump bottle is good.

Using a piece of metal pipe roll the grit into the scored sheet.
Make sure that you do not contaminate one grit with another. I keep
each sheet in a separate bag, labeled. Also unless you use a steel
roller which you must clean thoroughly between grits, use a separate
roller for each grit.

Next using your soap/water mix, rub the stone back and forth across
the copper plate starting with the coarsest grit. As you get to the
level of smoothness you need then clean the stone thoroughly and go
to the next finer grit. Rub until all scratches are gone and proceed
down to finer grit. I start with 100 grit, then 400, then 1200.

For polishing you have a number of options; such as 50,000 and
100,000 diamond grit; a copper or Lucite plate (unscored) Lucite
being my favorite with either Cerium or Aluminum oxide and again use
the soap/water lubricant.

A good and inexpensive book to use is “Facet Cutters Handbook” by
Edward Soukup - ISBN 910652-06-6. You just would ignore the parts
about setting angles.

From a hand-facetors perspective. Note: you can do the rubbing while
watching TV as is does take a little while. Bonus is that it is
quite inexpensive and the tools don’t take up a lot of space.

If you need further details email me direct.

the Rocklady
Karen Seidel-Bahr @Rocklady
May your gems always sparkle.


#8

This is possible, but it won’t be easy. I started with a Dremel on
opal and eventually learned much more.

The best suggestion I have is to buy a book on cutting. You can
work this stuff dry with the right equipment. And in the final
analysis, what’s going to be extremely hard with the Dremel is
polishing.

Again. Buy a book and someone mentioned, start with some other
material. You can get cheap quartz at any rock shop.